HG_REPOSITORIES/LPP/INSTRUMENTATION/VHD_Lib Files · lib/lpp/lpp_uart/BaudGen.vhd

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        Alexis
    
Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\

              r19
            
      ------------------------------------------------------------------------------

      --  This file is a part of the LPP VHDL IP LIBRARY

      --  Copyright (C) 2009 - 2010, Laboratory of Plasmas Physic - CNRS

      --

      --  This program is free software; you can redistribute it and/or modify

      --  it under the terms of the GNU General Public License as published by

      --  the Free Software Foundation; either version 3 of the License, or

      --  (at your option) any later version.

      --

      --  This program is distributed in the hope that it will be useful,

      --  but WITHOUT ANY WARRANTY; without even the implied warranty of

      --  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

      --  GNU General Public License for more details.

      --

      --  You should have received a copy of the GNU General Public License

      --  along with this program; if not, write to the Free Software

      --  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

      -------------------------------------------------------------------------------

        Alexis
    
Minor changes

              r38
            
      --                    Author : Alexis Jeandet

      --                     Mail : alexis.jeandet@lpp.polytechnique.fr

      ----------------------------------------------------------------------------

        Alexis
    
Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\

              r19
            
      library IEEE;

      use IEEE.numeric_std.all;

      use IEEE.std_logic_1164.all;

        alexis
    
Improved doxygen html output, improved documentation on some VHDL and C files.

              r67
            
      --! This is an automatic Baud generator. To synchronize baudrate, it measure the smalest time between two transitions of RXD. So to set baud rate, the device connected to this UART should send at least one data such as 0xA5 (0b10100101) witch gives a lot of transition of one bit length.

      --! \author Alexis Jeandet alexis.jeandet@lpp.polytechnique.fr

        Alexis
    
Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\

              r19
            
      entity BaudGen is

      port(

        alexis
    
Improved doxygen html output, improved documentation on some VHDL and C files.

              r67
            
          clk         :   in  std_logic; --! System clock

          reset       :   in  std_logic; --! System reset

          Capture     :   in  std_logic; --! baudrate reset so if you want to synchronize again the baudrate generator, usefull if you whant to decrease speed.

          Bclk        :   out std_logic; --! Output baud clock

          RXD         :   in  std_logic; --! UART Reception pin used to sample baudrate

          BTrigger    :   out std_logic_vector(11 downto 0) --! Current value of the frequency divider

        Alexis
    
Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\

              r19
            
      );

      end BaudGen;

      architecture ar_BaudGen of BaudGen is

      signal  cpt         :   std_logic_vector(11 downto 0) := (others => '0');

      signal  errorFlag   :   std_logic;

      signal  triger      :   std_logic_vector(11 downto 0) := (others => '0');

      signal  RX_reg      :   std_logic:='1';

      begin

      BTrigger    <=  triger;

      BaudGeneration: 

      process(clk,reset)

      begin

          if reset = '0' then

              cpt         <=  (others => '0');

              triger      <=  (others => '1');

              errorFlag   <=  '0';

          elsif clk'event and clk = '1'then

              RX_reg  <=  RXD;

              if capture = '1' then

                  cpt     <=  (others => '0');

                  triger  <=  (others => '1');

                  errorFlag   <=  '0';

              else

                  if RX_reg /= RXD then

                      cpt         <=  (others => '0');

                      if cpt = std_logic_vector(TO_UNSIGNED(0,12)) then

                          errorFlag   <=  '1';

                      elsif errorFlag = '1' then

                          triger      <=  cpt;

                          errorFlag   <=  '0';  

                      else

                          errorFlag   <=  '1';              

                      end if;

                  else

                      if cpt = triger then

                          cpt         <=  (others => '0');

                          errorFlag   <=  '0';

                      else

                          cpt     <=  std_logic_vector(unsigned(cpt) + 1);

                      end if;

                  end if;

              end if;

          end if;

      end process;

      process(clk)

      begin

          if clk'event and clk = '1' then

              if cpt = std_logic_vector(TO_UNSIGNED(0,12)) then

                  Bclk    <=  '0';

              elsif cpt = '0' & triger(11 downto 1) then

                  Bclk    <=  '1';

              end if;

          end if;

      end process;

      end ar_BaudGen;

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Alexis Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\	r19	------------------------------------------------------------------------------
		-- This file is a part of the LPP VHDL IP LIBRARY
		-- Copyright (C) 2009 - 2010, Laboratory of Plasmas Physic - CNRS
		--
		-- This program is free software; you can redistribute it and/or modify
		-- it under the terms of the GNU General Public License as published by
		-- the Free Software Foundation; either version 3 of the License, or
		-- (at your option) any later version.
		--
		-- This program is distributed in the hope that it will be useful,
		-- but WITHOUT ANY WARRANTY; without even the implied warranty of
		-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		-- GNU General Public License for more details.
		--
		-- You should have received a copy of the GNU General Public License
		-- along with this program; if not, write to the Free Software
		-- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		-------------------------------------------------------------------------------
Alexis Minor changes	r38	-- Author : Alexis Jeandet
		-- Mail : alexis.jeandet@lpp.polytechnique.fr
		----------------------------------------------------------------------------
Alexis Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\	r19	library IEEE;
		use IEEE.numeric_std.all;
		use IEEE.std_logic_1164.all;

alexis Improved doxygen html output, improved documentation on some VHDL and C files.	r67	--! This is an automatic Baud generator. To synchronize baudrate, it measure the smalest time between two transitions of RXD. So to set baud rate, the device connected to this UART should send at least one data such as 0xA5 (0b10100101) witch gives a lot of transition of one bit length.

		--! \author Alexis Jeandet alexis.jeandet@lpp.polytechnique.fr
Alexis Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\	r19
		entity BaudGen is

		port(
alexis Improved doxygen html output, improved documentation on some VHDL and C files.	r67	clk : in std_logic; --! System clock
		reset : in std_logic; --! System reset
		Capture : in std_logic; --! baudrate reset so if you want to synchronize again the baudrate generator, usefull if you whant to decrease speed.
		Bclk : out std_logic; --! Output baud clock
		RXD : in std_logic; --! UART Reception pin used to sample baudrate
		BTrigger : out std_logic_vector(11 downto 0) --! Current value of the frequency divider
Alexis Migrating from GPLV2 to V3, and cleand some files. /!\ Unstable /!\	r19	);
		end BaudGen;


		architecture ar_BaudGen of BaudGen is
		signal cpt : std_logic_vector(11 downto 0) := (others => '0');
		signal errorFlag : std_logic;
		signal triger : std_logic_vector(11 downto 0) := (others => '0');
		signal RX_reg : std_logic:='1';

		begin


		BTrigger <= triger;


		BaudGeneration:
		process(clk,reset)
		begin
		if reset = '0' then
		cpt <= (others => '0');
		triger <= (others => '1');
		errorFlag <= '0';
		elsif clk'event and clk = '1'then
		RX_reg <= RXD;
		if capture = '1' then
		cpt <= (others => '0');
		triger <= (others => '1');
		errorFlag <= '0';
		else
		if RX_reg /= RXD then
		cpt <= (others => '0');
		if cpt = std_logic_vector(TO_UNSIGNED(0,12)) then
		errorFlag <= '1';
		elsif errorFlag = '1' then
		triger <= cpt;
		errorFlag <= '0';
		else
		errorFlag <= '1';
		end if;
		else
		if cpt = triger then
		cpt <= (others => '0');
		errorFlag <= '0';
		else
		cpt <= std_logic_vector(unsigned(cpt) + 1);
		end if;
		end if;
		end if;
		end if;
		end process;


		process(clk)
		begin
		if clk'event and clk = '1' then
		if cpt = std_logic_vector(TO_UNSIGNED(0,12)) then
		Bclk <= '0';
		elsif cpt = '0' & triger(11 downto 1) then
		Bclk <= '1';
		end if;
		end if;
		end process;


		end ar_BaudGen;